A fall arrester or fall arresting device is typically included in a harness worn by an individual working at elevated heights; the fall arrester reduces injuries that might occur if the worker falls from his or her work station.
More specifically, the present invention includes a protection device or fall arrester for a user thereof for arresting a fall or potential fall of a user from an elevated location, comprising: a frame; a spool rotationally supported on the frame, a length of flexible connecting member; including one of a length of webbing or string or wire; having one end secured to the spool and a second end adapted to be linked to a connector including a hook for securing the second end to a weight supporting member of a nearby structure. The connecting member is capable of being pulled from the spool and capable of being rewound upon the spool by a rewind spring during an unlocked mode of operation. The fall arrester also includes a torsion bar having a first end secured to one side of the spool and rotatable with the spool and a second end connected to a first lock wheel capable of selectively being locked from rotation when the device has entered into a locked mode of operation. If the user falls, the torsion bar twists through a given number of turns after the locked mode is entered and the connector member and spool are loaded. The fall arrester includes a web counting mechanism which is active during the unlock mode of operation and causes the fall arrester to enter into the locked mode of operation when a determinable length of the flexible connecting member has been protracted from the spool or alternately remains on the spool. This function insures that there will be a sufficient amount of the connector member (webbing or lanyard) on the spool to enable the torsion bar to thereafter rotate through the given number of revolutions if the user subsequently falls. The fall arrester, in its preferred embodiment, includes an acceleration sensor able to initiate the fall arrester entering into a locked mode of operation when the connecting member is being protracted at a first dynamic level independent of the length of connecting member that has been protracted from the spool.